melted plastic not a good thing

[Chris N]

hi all
after a very twisty run with a friend on the back the rear brake fealt spongy by the time i got home,the next day i had a look why and found melted plastic.

i had not noticed the back brake dragging,the caliper has had new pistons/seals,i checked both pistons move freely,not sure why one side wore badly and overheated and not both.

i have ordered a seal kit for the rear master cylinder which i have not changed and some new pads.

[HOCAdmin]

Hi Chris.

With opposed piston calipers it's almost impossible to have the pistons move at exactly the same time, one piston invariably 'leads'.

On the V1000, the caliper 'floats' with the parallelogram mount having a sintered bronze bush as one of the axle spacers...  This bush wears, leading to axial movement as well as radial movement and allows the caliper to float from side to side too.

So...  By all means examine and rebuild the caliper - it's clearly gotten very hot.  When you do, be sure to check that the fluid is returning freely from both sides as the pistons are pushed back in.

But I would definitely recommend checking the floating mount and the bush, and also the condition and adjustment of the torque arm between the rear of the crankcase and the floating caliper mount.  All of the fittings should be free to move and adjusted such that the caliper is permitted to rotate freely about the axle as the suspension moves.

Hope that helps.

[Dave Snr]

Hi Chris,

Another thing to check is that the pads are not a tight fit in the caliper. They need to be quite a loose fit as they expand with the heat from braking.
Never had a problem with pads sticking in Hesketh Brembo calipers, but have experienced it in 60's Jaguar calipers. The aftermarket pads were too tight in the calipers and needed the side edges filing to give the right fit.
In my Hesketh I use EBC FA18 pads, but the ones in your photo look different.

Dave H